If combined with a CELTA and experience, it should be accepted. I'd take the MA that will be the most useful for you long term wherever you want to live. If you plan to teach EFL/ESL forever, get it in TEFL or Applied Linguistics.

As for the MED... Not as beneficial as a MA applied linguistics/TESOL/TESL.

The problem is that if you want to teach English, they prefer to have an english related degree. If you want to teach education courses most of the uni's in the gulf want that Phd.

You are just as limited with the MED in the gulf as with the MA in applied linguistics/TESL as in the US and UK.

Can you get a uni job teaching english with the MED, CELTA and experience... yes. But some places don't look at it as equal to the MA in applied linguistics. It is weird.

In the states/UK the MED is more marketable.... Here in the UAE, the Applied linguistics/TESL appears more marketable.

as for your question about the DELTA... It all depends on who is doing the hiring. I have had Chairs who look down on the US/Australian MA's vs a Delta because they think the DELTA is more hands on which they think means it is better. My MA had a semester long teaching practicum and a whole lot more theory than a DELTA...But there is a long running "debate" about which is better... I'll take my American MA with my teaching practicum over a Brit DELTA any day of the week and twice on sundays... But there are others who will argue the opposite.

I think the MEd gives the best coverage across all sectors and countries. Could I get a job at a university in Dubai with MEd/ BA/ CELTA + tertiary experience ?

Although I'm presently teaching in Saudi Arabia, I have an MA in Teaching (MAT) in Multidisciplinary Studies with a focus in TEFL (18 credits including a semester-long ESOL practical component). If the MEd program you're interested in allows for a similar emphasis or focus (and includes a teaching practicum), then this is an option you could consider.